When I wrote the headline "Hillary's heel," I was thinking of Achilles, not Bill, though the former president is usually within nipping range of his wife's pantsuit hem.

Hillary Clinton's Achilles' heel is her very Clinton-ness. Just as her husband was willing to parse the meaning of the word "is" rather than admitting his foibles early on and preventing the national torture of watching his extramarital sex life unfold, Hillary has mastered the habit of teetering along the knife's edge of truth.

Like a gymnast on a balance beam, she manages to stay within the narrow parameters of lawfulness without losing her footing. But her long history of avoiding provable infractions despite hundreds of hours of investigations and millions in taxpayer expense â€” from Whitewater to Benghazi to her private email server â€” may soon come to an end, not with a gold medal but with an Olympian loss of trust.

A batch of emails released Monday from Huma Abedin, Clinton's deputy chief of staff at the State Department, shows how Clinton Foundation donors sought favors. Not all requests appear to have been granted, but the coziness between State and the Clinton family charity raise questions about the integrity of Hillary's promise to President Obama to build a firewall between the two institutions when she became his secretary of state.

Among examples reported by The Washington Post:

Sports executive Casey Wasserman, whose own family's charitable organization has given the Clinton Foundation between $5 million and $10 million, and whose investment company paid Bill Clinton $3.13 million in consulting fees in 2009 and 2010 â€” sought a visa for a British soccer player with a criminal past. It was not granted.

The crown prince of Bahrain, Salman bin Hamad al-Khalifa, whose government had given $50,000 to the foundation, requested a last-minute meeting with the secretary of state. Granted.

U2's Bono, a regular at foundation events, asked for help in broadcasting a live link to the International Space Station during a concert tour. Response from State: "No clue."

These discoveries, among others, may not amount to much in terms of actual favors, but they cast doubt on the integrity of Hillary Clinton's word. They also go a long way toward confirming her critics' allegation that the Clintons were in a global pay-for-play arrangement.

One crucial fact is no longer in dispute: Foundation donors got access to the State Department.

The emails became public through a lawsuit filed by Judicial Watch, a conservative watchdog group, and were among 725 pages of Abedin's correspondence. The stash also included 20 emails between Abedin and Clinton that weren't included in the 55,000 pages previously provided to State. Meanwhile, the FBI has turned over about 15,000 other emails and documents to State that were discovered during the agency's investigation of Clinton's private server.

Judicial Watch is trying to get these released as well. In the meantime, a State Department spokesman says that many of them were plainly personal.

As if these developments weren't problematical enough, former Secretary of State Colin Powell last weekend denied Clinton's claim that he advised her to use a private server, as he had done, saying, "Her people are trying to pin it on me." According to Powell, Clinton had been using her server for at least a year before the two discussed how he had managed his email.

Whether this constitutes a "lie" to the FBI, as some are claiming, or the result of a faulty memory likely will keep busy bees buzzing for a while. But Clinton has bigger worries as more emails continue to trickle out, revealing who knows what. But what we already know from FBI Director James Comey is that his agency's investigation found insufficient evidence to charge Clinton, though he did say her handling of classified information was "extremely careless" and that she falsely testified to the House Oversight Committee on Benghazi that there was no classified material in any of her email.

Other than that, Mrs. Lincoln ...

To Republicans, Clinton is a serial liar. To Democrats, she is the perennial target of a right-wing conspiracy. Both appear to be marginally correct. The question for voters may come down to this: How much, if any, substantive harm has Clinton's lack of absolute clarity on a given subject or event caused?

The only definitive answer thus far is that she has deeply damaged whatever public trust remained --- and for a candidate, this can be fatal.